An antenna integrated with a solar battery is known in the art, for example, as disclosed in Japanese Patent Publication No. H10-270925. The prior art antenna, which is composed of an electric-conductor film and an array-antenna element, is formed on a solar battery. The electric-conductor film of the antenna is made of metallic material, which is formed in a thin film. Since resistivity of the electric-conductor film is high, loss of the antenna as a whole is large. Antenna gain is thereby largely decreased.